public class Example4_9 {
   public static void main(String args[]) {
      SIM simone = new SIM(13889776509L);
      MobileTelephone mobile = new MobileTelephone();
      mobile.setSIM(simone);
      System.out.println(""+mobile.lookNumber());
      SIM simTwo = new SIM(15967573567L);
      mobile.setSIM(simTwo);
      System.out.println(""+mobile.lookNumber());
   }
}
